The Japanese space agency JAXA announced in August that its Hayabusa probe 2, which arrived at the 3,000-foot-wide asteroid Ryugu in June, will attempt to send a pair of special rovers to the surface of the extraterrestrial rock.

Now, after a lengthy space travel from Earth, the probe has finally deployed the two rovers called MINERVA-II1A and MINERVA-II1B, which were designed to study the asteroid. Space reported that the event happened on September 21, when the mother ship was about 180 feet above the rocks’ surface.

Landing probes on asteroids has proved difficult. The only probes that managed to have a soft touchdown on an asteroid are the original Hayabusa probe, which landed on the surface of the asteroid Itokawa in 2003; and NASA’s Near Earth Asteroid Rendezvous-Shoemaker spacecraft, which landed on asteroid Eros in 2001.

If all goes as planned, the Minerva-II1 probes would have drifted down to touch down on the dusty surface of Ryugu.

JAXA officials confirmed clear signals from the two rovers after their deployment, but they admitted having lost contact, which they attribute to the rotation of the asteroid.

Officials said that the MINERVA-II1 duo is currently on the far side of the asteroid and they are working to confirm images that capture the landing of the robots. It may take a couple more days to confirm that the rovers are ready to perform their scientific duties.

MINERVA-II1A and MINERVA-II1B carry with them a range of scientific gear, which includes seven cameras, as well as temperature and optical sensors. The probes were designed to hop from place to place on the surface of their target asteroid.

Mission members explained that gravity on the asteroid’s surface is weak, so a rover propelled by wheels or crawlers would float upwards once it starts to move.

“This hopping mechanism was adopted for moving across the surface of such small celestial bodies,” mission team members said.

“The rover is expected to remain in the air for up to 15 minutes after a single hop before landing, and to move up to 15 m [50 feet] horizontally.”

The Hayabusa 2 mission, which was launched in 2014, will grab samples from Ryugu and return these materials to Earth. The goal of the mission is to learn more about the target asteroid and get a better understanding of what asteroids are made of.

Astronomers are keen on studying asteroids like Ryugu because these objects are believed to be remnants of the early solar system and remained relatively unchanged over the past 4.5 billion.